Disclosed are DNA sequences encoding hyaluronic acid synthase that are employed to construct recombinant cells useful in the production of hyaluronata synthase and hyaluronic acid (HA). In preferred aspects, chromosomal DNA encoding the HA synthase gene, hasA, was cloned from a Streptococcus pyoganas genomic library. These vectors were used to transform host cells such as E. coli and acapsular Streptococci to produce hyaluronic acid. Resultant transformants were screened to identify colonies which have incorporated HA synthase DNA in a form that is being actively transcribed into the corresponding HA synthase enzyme. These colonies were selected and employed in the production of hyaluronic acid.